Reverse lock for vehicles



Sept. 24, 1940. QQHUNTER 2,215,586

REVERSE LOCK FOR VEHICLES Filed Dec. 5, 1938 2 Sheets-Sheet 1 Fi .1 a; )4?

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3 \a w Z2 7 4 g g m 0 'INVENTOR cyss EEO- HUNTER BY Q /g 2 H15 ATTORNEY Sept. 24, 1940. c. 0. HUNTER REVERSE LOCK FOR VEHICLES Filed Dec. 5, 1938 2 Sheets-Sheet 2 .Fig. 5

INVENTOR 012257520. HUNTER BY fig.

/'//5 ATTORNEY Patented Sept. 24, 1940 REVERSE LOCK FOR VEHICLES Chester 0. Hunter, San Anselmo, Calif., assignor of one-half to Phillips S. Davies, San Francisco,

Calif.

Application December 5, 1938,Serial No. 243,969

19 Claims.

My invention relates to an automatic locking mechanism for preventing a vehicle, such as an automobile, from moving backward at such times when reverse movement is not desired.

It is among the objects of my invention to provide areverse look of the character described which permits free forward movement of the vehicle, but looks the vehicle against reverse movement upon any tendency of the vehicle to roll backward when stopped on a hill.

Another object is to provide means for rendering the lock inactive upon shifting the vehicle into reverse gear.

Still another object is to provide a ratchet and pawl locking mechanism having means for insuring full and positive engagement of a locking pawl with the ratchet wheel.

A further object is to provide a locking mechanism of the character described having a pilot pawl for actuating the locking pawl.

A still further object includes the provision of a locking pawl having a movable pivot and means for releasably holding the pawl pivot.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of my invention. It is to be understood that I do not limit myself to this disclosure of species of my invention as I may adopt variant embodiments thereof within the scope of the claims.

Referring to the drawings:

Figure 1 is a transverse vertical sectional view of the reverse lock; and

Figure 2 is an axial sectional view taken in a plane indicated by line 2-2 of Figure 1.

Figure 3 is a horizontal sectional view taken in a plane indicated by line 33 of Figure 1, showing the releasable holding mechanism; and

Figure 4. is a similar view showing the holding mechanism after release.

Figures 5 to 8 are transverse vertical sectional views of the ratchet and pawl structure apart from the housing and illustrating the parts in several different positions of operation.

Figure 9 shows a modified construction for the pilot pawl.

In reverse lock mechanisms relying upon engagement of a pawl with a ratchet wheel to look a vehicle against rearward movement, it is important that the locking pawl engage fully and positively with the ratchet wheel. If the pawl does not engage properly the lock is not-dependable for holding the car, and the tips of the pawl and ratchet teeth receive undue wear. Another defect locksofthis character is that, once locked, they are dimcult to release when it is desired to shift into reverse gear. My improved reverse locking mechanism embodies a pilot pawl for actuating the locking pawl to insure positive engagement of the latter with the ratchet 'wheel; 5 and also embodies a movable pivot mounting for the locking pawl so that the latter may be readily released.

In terms of broad-inclusion, my reverse lock for vehicles comprises a ratchet wheel, a pilot 10 pawl engageable with the ratchet wheel and having a movable pivot, a locking pawl also having a movable pivot and engageable with the ratchet wheel upon movement of the pilot pawl pivot, and means for releasably holding the locking pawl pivot. Means responsive to rotation of the ratchet wheel is also provided for moving the pilot pawl into and out of engagement with the wheel. The ratchet wheel is mounted for rotation with a part, such as the drive shaft of the vehicle; and 20 the releasable holding means for the locking pawl pivot is preferably operably connected with the reverse gear shift of the vehicle.

In greater detail, and referring to the drawings, the reverse locking mechanism of my invention 25 comprises a housing 2 mounted on a fixed part or frame of the vehicle. As applied to an ordinary automobile I prefer to mount the housing 2 directly on the tail end of transmission gear case 3, by suitable studs 4, so that drive shaft 6 pro- 30 jects into the housing. An end bell l is provided on the housing and preferably encloses speedome eter gears 8. Part 9 of the universal joint is splined on the tail end of shaft 6 in the usual manner, and an oil seal II is preferably interposed between end bell I and part 9.

A ratchet wheel I2 is arranged inthe housing and is mounted for rotation with a part of the vehicle. In the particular arrangement -I have shown, ratchet wheel I2 is splined directly 40 on drive shaft 6, but it is understood that this is merely for purposes of illustration. The ratchet wheel could be connected in any other desired manner to rotate with a wheel of the vehicle. I Means are provided for locking the vehicle against reverse movement. For this purpose a pair of locking pawls l3 are provided in the housing for engagement with the ratchet wheel, and 50 are mounted on pivot pins I4 fastened to an anchor plate [6. During normal operation of the unit, anchor plate I6 is held so that pivot pins M are fixed; and suitable springs I! are arranged between the pawls and pivot pins to 55 urge the pawls toward engagement with the ratchet wheel.

Means responsive to movement originating in the ratchet wheel are provided for moving the locking pawls into and out of engagement with the wheel. In order to insure full and positive engagement of the locking pawls the latter are controlled by a pilot pawl l8 pivotally mounted by a pin [9 on an actuating plate 2| and urged into engagement with the ratchet wheel by a spring 22. Actuating plate: 21 is oscillatably mounted on a hub portion 25 of the housing and is urged toward its counterclockwise (as viewed in Figure 1) limit of oscillation by a spring 23; this direction of plate movement being limited by stop 24.

Thus, when pilot pawl I8 is engaged with the ratchet wheel and the latter turns backwards (clockwise is viewed in Figure 1), the actuating plate is also turned clockwise; and when the wheel turns forward the actuating plate is returned counterclockwise to its limit stop 24 by spring 23. Cam surfaces 26 are arranged on the actuating plate to engage rollers 21 on the locking pawls, so that when plate 2! turns clockwise the pawls l3 are moved into engagement with the ratchet wheel, and when the plate turns counterclockwise the locking pawls are moved out of engagement with the wheel. In other words, when pivot pin I9 of the pilot pawl moves back the locking pawls are engaged, and when the pivot pin moves ahead the locking pawls are disengaged.

Means are provided for moving the pilot pawl out of engagement with the ratchet wheel upon forward (counterclockwise) rotation of the wheel, and for moving the pilot pawl into engagement with the wheel upon backward (clockwise) rotation of the wheel. This is accomplished by a pair of cam plates 28 oscillatably mounted on the ratchet wheel and frictionally pressed against the sides of the latter by springs 29, so that when the wheel rotates, cam plates 28 tend to rotate with it. The cam plates are recessed out at 30 to allow pilot pawl 18 to engage the ratchet wheel, and an end of each notch is rounded to provide a cam surface 3| for moving and holding the pilot pawl out of engagement with the wheel when the latter is rotating in its forward (clockwise) direction; the cam plates being limited in their forward direction of oscillation by abutment with the rear ends of pawls I3. See Figure 5. Thus, when the car is moving forwardly the reverse lock is inactive.

When the car starts to roll back, ratchet wheel l2 turns clockwise and carries cam plates 28 with it to allow pilot pawl 18 to drop down into engagement with a tooth of the ratchet wheel. Further clockwise movement of the wheel causes pilot pawl pivot I!) to move back and rotate actuating plate 2| clockwise. Rollers 2! f the locking pawls then roll inwardly on cam surfaces 26 to move locking pawls l3 into engagement with the teeth of the ratchet wheel. See Figure 6. Ratchet wheel I2 is thus locked against further clockwise rotation, and the car is held against further backward movement. The car is of course free toqgo forward at any time, because counterclockwise movement of the ratchet wheel operates to disengage all the pawls.

Means are also provided for releasing the lock and rendering it inactive when the car is put in reverse gear. For this purpose a releasable holding mechanism is provided for anchor plate l6 which carries locking pawls [3. Plate 16 is mounted for oscillation on hub 25, and has a neck portion 32 carrying a roller 33 and projecting through a slot 34 in the upper portion of the housing. The anchor plate is held in normal position as shown in Figure 3 by an abutment link 36 pivoted on a fixed pin 31 and urged into abutting relation with neck 32 by a spring 38.

Link 35 is moved out to release the anchor plate by a plate-like arm 39 pivoted on a fixed pin 4| and having an abutment pin 42 thereon for engaging link 36 to move the latter sideways. Arm 39 has a central opening 43 to clear neck 32, and is urged toward closed or holding position by spring 44. When the parts are closed a cam surface 45 on link 36 operates to shove neck 32 toward the left, and the link is positively held against opening by an interlocking lug 46 on arm 39. A suitable cap 4! is provided for enclosing this mechanism, and a rod 48 is arranged to connect arm 39 with the reverse gear shift of the regular transmission; the connection being such that the anchor plate is released whenever the gears are shifted into reverse, and held whenever the gears are shifted to neutral or to some forward speed.

The effect of releasing anchor plate I6 is to render the reverse lock inactive because the anchor plate is free to rotate clockwise and cause rollers 21 to roll out on cam surfaces 26 to disengage locking pawls 53. It is to be noted that if anchor plate I6 is released when the pawl mechanism is in reverse lock, the locking pawl rotates away from the tooth at the same time it swings out. This is important because it permits free and easy disengagement of the locking pawl even though it is taking the locking thrust of the ratchet wheel.

Means are also provided for disengaging the pilot pawl at such times when the locking pawls are disengaged by release of anchor plate I6. This is accomplished by means of a stop ring 49 journaled about shaft 6 and held by a post A lip 52 on this ring abuts lug 53 on pilot pawl l8 when the latter turns back with the ratchet wheel, thus causing the pilot pawl to move up out of engagement with the wheel. Figure 7 shows the relation of the parts at the time pawl I8 is abutting stop 52 and has been lifted out of engagement with the ratchet wheel.

As soon as pawl I8 is disengaged its spring 22 tends to bring it back down again, but this is prevented by a. notch 54 at the other end of cam recess 30 and into which pawl l8 drops. At this time cam plates 28 are tending to turn clockwise so that notch 54 is under the pawl head when it drops down. See Figure 8. The ratchet wheel is then free to run clockwise to permit the car to go backwards in reverse gear.

Whenever the transmission is subsequently shifted back into neutral or into' a forward speed, the anchor plate holding means is reset, and any slight forward movement of the car causes pilot pawl it to be dislodged from.- notch 54 and reengaged with the ratchet wheel or carried up on cam surfaces 3i for forward operation. In fact, the movement required to dislodge pawl I8 from notch 54 is so slight that reengagement of the pawl with the ratchet wheel occurs by reason of the relative movements that inherently exist whenever a transmission is shifted out of reverse gear. The reverse lock is therefore reconditioned for operation by the mere act of shifting'out of reverse gear, although no actual forward movement of th'ecar has occurred.

Figure 9 showsa modified construction for'the pilot pawl/ In this case the pawl is made in two sections, pivoted side by side. Each section is spring pressed and is capable of engaging the ratchet independently of the other; and one section has a nose 56 disposed slightly ahead of the other, so that if one section of the pawl should accidently slip out of or fail to engage the ratchet tooth the other section will engage it.

I claim:

l. A reverse lock for vehicles, comprising a ratchet wheel, a pilot pawl engageable with the ratchet wheel and having a movable pivot, a locking pawl also having a movable pivot and engageable with the ratchet wheel upon movement of said pilot pawl pivot, and means for releasably holding said locking pawl pivot.

2. A reverse lock for vehicles, comprising a ratchet wheel, a pilot pawl engageable with the ratchet wheel and having a movable pivot, a locking pawl also having a movable pivot and engageable with the ratchet wheel upon movement of said pilot pawl pivot, means for releasably holding said locking pawl pivot, and means responsive to rotation of the ratchet wheel for moving the pilot pawl into and out of engagement with said wheel.

3. A reverse lock for vehicles, comprising a ratchet wheel, a pilot pawl engageable with the ratchet wheel and having a movable pivot, a looking pawl also having a movable pivot and engageable with the ratchet wheel upon movement of said pilot pawl pivot, means for releasably holding said locking pawl pivot, and means responsive to rotation of the ratchet wheel for moving the pilot pawl out of engagement with the wheel upon forward rotation of the latter and for moving the pawl into engagement therewith upon reverse rotation of the wheel.

4. A reverse lock for vehicles, comprising a ratchet wheel, a pilot pawl engageable with the ratchet wheel an dhaving a movable pivot, a locking pawl also having a movable pivot and engageable with the ratchet wheel upon movement of said pilot pawl pivot, means for releasably holding said locking pawl pivot, means responsive to rotation of the ratchet wheel for moving the pilot pawl out of engagement with the wheel upon forward rotation of the latter and for moving the pawl into engagement therewith upon reverse rotation of the wheel, and means for moving the pilot pawl out of engagement with the wheel upon release of said locking pawl pivot.

5. A reverse lock for vehicles, comprising a ratchet wheel, a pilot pawl engageable with the ratchet wheel and having a movable pivot, a looking pawl also having a movable pivot and engageable with the ratchet wheel upon movement of said pilot pawl pivot, means for releasably holding said locking pawl pivot, means responsive to rotation of the ratchet wheel for moving the pilot pawl out of engagement with the wheel upon forward rotation of the latter and for moving the pawl into engagement therewith upon reverse rotation of the wheel, means for moving the pilot pawl out of engagement with the wheel upon release of said locking pawl pivot, and means for holding the pilot pawl out of engagement with said wheel after release of the locking pawl pivot.

6. A reverse lock for vehicles, comprising a ratchet wheel, a locking pawl engageable with the ratchet Wheel, a pawl actuating plate engageable with the locking pawl for moving the latter into and out of engagement with the wheel, and a pilot pawl pivotally mounted on the actuating plate and engageable with the wheel for moving said actuating plate.

7. A reverse lock for vehicles, comprising a ratchet wheel, a movable anchor plate, a locking pawl pivotally mounted on the anchor plate and engageable with the ratchet wheel, means for releasably holding the anchor plate, a pawl actuating plate engageable with the locking pawl for moving the latter into and out of engagement with the wheel, and a pilot pawl pivotally mounted on the actuating plate and engageable with the wheel for moving said actuating plate.

8. A reverse lock for vehicles, comprising a ratchet wheel, a pawl engageable with the ratchet wheel and having a movable pivot, and a cam means movable in response to rotation of the ratchet wheel for moving the pawl into and out of engagement with said wheel.

9. A reverse lock for vehicles, comprising a ratchet wheel, a pawl engageable with the ratchet wheel and having a movable pivot, and a cam plate movable inresponse to rotation of the ratchet wheel for moving the pawl out of engagement with the wheel upon forward rotation of the latter and for moving the pawl into engagement therewith upon reverse rotation, of the wheel.

10. A reverse lock for vehicles, comprising a ratchet wheel, a pawl engageable with the ratchet wheel and having a movable pivot, a cam plate movable in response to rotation of the ratchet wheel for moving the pawl out of engagement with the wheel upon forward rotation of the latter and for moving the pawl into engagement therewith upon reverse rotation of the wheel, and stop means for moving the pawl out of engagement with the wheel upon reverse rotation of the latter.

11. A reverse lock for vehicles, comprising a ratchet wheel, a pawl engageable with the ratchet Wheel and having a movable pivot, a cam plate movable in response to rotation of the ratchet wheel for moving the pawl out of engagement with the wheel upon forward rotation of the latter and for moving the pawl into engagement therewith upon reverse rotation of the wheel, stop means for moving the pawl out of engagement with the wheel upon reverse rotation of the latter, and means on the cam plate for holding the pawl out of engagement with said wheel after disengagement by said stop means.

12. A reverse lock for vehicles, comprising a ratchet wheel, a movable anchor plate, a locking pawl pivotally mounted on the anchor plate and engageable with the ratchet wheel, means for releasably holding the anchor plate, a pawl actuating plate engageable with the locking pawl for moving the latter into and out of engagement with the wheel, a pilot pawl pivotally mounted on the actuating plate and engageable with the wheel for moving said actuating plate, and a cam plate movable in response to rotation of the ratchet wheel for moving the pilot pawl out of engagement with the wheel upon forward rotation of the latter and for moving the pilot pawl into engagement therewith upon reverse rotation of the wheel.

13. A reverse lock for vehicles, comprising a ratchet wheel, a movable anchor plate, a locking pawl pivotally mounted on the anchor plate and engageable with the ratchet wheel, means for on the actuating plate and engageable with the wheel for moving said actuating plate, a cam plate movable ,in response to rotation of the ratchet wheel for moving the pilot pawl out of engagement with the wheel upon forward rotation of the latter and for moving the pilot pawl into engagement therewith upon reverse rotation of the wheel, and stop means for moving the pilot pawl out of engagement with the wheel upon release of said anchor plate.

14. A reverse lock for vehicles, comprising a ratchet wheel, a movable anchor plate, a locking pawl pivotally mounted on the anchor plate and engageable with the ratchet wheel, means for releasably holding the anchor plate, a pawl actuating plate engageable with the locking pawl for moving the latter into and out of engagement with the wheel, a pilot pawl pivotally mounted on the actuating plate and engageable with the wheel for moving said actuating plate, a cam plate movable in response to rotation of the ratchet wheel for moving the pilot pawl out of engagement with the wheel upon forward rotation of the latter and for moving the pilot pawl into engagement therewith upon reverse rotation of the wheel, stop means for moving the pilot pawvl out of engagement with the wheel upon release of said anchor plate, and means on the cam plate for holding the pilot pawl out of engagement with said wheel after disengagement by said stop means.

15. A reverse lock for vehicles, comprising a ratchet wheel, a locking pawl engageable with the wheel, a cam for controlling engagement of the locking pawl, and a pilot pawl engageable with the wheel for moving said cam.

16. A reverse lock for vehicles, comprising a ratchet wheel, a locking pawl engageable with the wheel, a cam for controlling engagement of the locking pawl, and a pilot pawl pivoted to the cam and engageable with the wheel for moving said cam.

17. A reverse lock for vehicles, comprising a ratchet wheel, a locking pawl engageable with the wheel, a spring for urging the pawl toward the wheel, a cam for holding the pawl out of engagement and movable to allow engagement thereof with said wheel, and a pilot pawl engageable with the wheel for moving said cam.

18. A reverse lock for vehicles, comprising a ratchet wheel, a locking pawl engageable with the wheel, a spring for urging the pawl toward the wheel, a cam for holding the pawl out of engagement and movable to allow engagement thereof with said wheel, a spring for urging the cam toward its pawl holding position, and a pilot pawl engageable with the wheel for moving said cam.

19. A reverse lock for vehicles, comprising a ratchet wheel, a locking pawl engageable with the wheel, a pilot pawl for controlling engagement of the locking pawl, and a cam movable in response to rotation of the wheel for controlling engagement of the pilot pawl.

CHESTER O. HUNTER. 

